PubMed Health⌕ Search

Biomedical subjects

J Pokora

Publications and source records attributed to J Pokora.

78 records · Page 5Linked to original sources
PubMedDate not supplied

Effects of histamine and cimetidine on the levels of serotonin and 5-hydroxyindoleacetic acid in various parts of the digestive tract and in the blood and brain of rats.

In the investigations on male Wistar rats it was demonstrated that histamine (0.05 and 0.5 mg/kg) decreased the serotonin level, without affecting the level of 5-HIAA in the stomach and duodenum. Contrary to this, cimetidine (15, 75 and 150 mg/kg) raised slightly the level of serotonin and decreased the 5-HIAA level in the stomach and duodenum. In the jejunum histamine in the lower dose raised the levels of serotonin and 5-HIAA, and in the higher dose it decreased only the concentration of serotonin. Cimetidine, on the other hand, only in the highest dose increased the serotonin level and decreased significantly the level of 5-HIAA. In the brain a rise of the serotonin level was observed only after histamine. No effects were observed of histamine and cimetidine on the blood serotonin level. Histamine reduced the number of enterochromaffinocytes in the duodenum. These results point to an evident interaction between the histaminergic and the serotoninergic structures in the digestive tract of rats.

Animals↗
PubMedDate not supplied

Effects of pentagastrin and oxyphenonium on the levels of serotonin and 5-hydroxyindoleacetic acid in different parts of the digestive tract, blood and brain of rats.

In the experiments of Wistar rats it was found that pentagastrin in a dose of 0.6 microgram/kg decreased the level of serotonin and increased that of 5-HIAA in the stomach wall, and in a dose of 3 micrograms/kg it had no effect on these parameters, while in a dose of 6 micrograms/kg it decreased only the serotonin level. Oxyphenonium 0.5 mg/kg increased only the 5-HIAA level in the stomach, and in a dose of 5 mg/kg it decreased also the level of serotonin, In the duodenum these substances remained unchanged after pentagastrin administration, but oxyphenonium 5 mg/kg caused a significant fall of serotonin and increase of 5-HIAA, which was associated with a decrease in the number of enterochromaffin cells. In the small intestine pentagastrin 0.6 micrograms/kg increased the serotonin level and decreased that of 5-HIAA, in a dose of 3 micrograms/kg it decreased only the 5-HIAA level, and in the 6 micrograms/kg dose it had no effect on the levels of these substances. Oxyphenonium increased only the intestinal 5-HIAA level but only when administered in a dose of 5 mg/kg. In the brain both higher doses of pentagastrin decreased the serotonin level, and all three doses raised significantly the 5-HIAA level. Oxyphenonium in the higher dose raised the brain serotonin level, but was without effect on the 5-HIAA level. The blood serotonin level was not changed by pentagastrin and oxyphenonium.

Animals↗
PubMedDate not supplied

[Activity of enkephalinase (EC.3.4.24.11). Neutral endopeptidase (NEP)in human digestive tract epithelial cells].

The activity was studied of enkephalinase (endopeptidase 24.11, neutral endopeptidase)--a membrane enzyme of epithelial cells within human digestive tract (in the stomach, duodenum, small intestine, ascending, descending and sigmoid colon, and rectum). The enzyme activity was determined by column method using the labelled substrate (H-D-AlaLeu)--enkephalin and the selective enkephalin inhibitor--thiorfan in the presence of bestatin and captopril--inhibitors of aminopeptidases and angiotensin converting enzyme respectively. The highest enkephalinase activity was found in the duodenal epithelium (77.3 8.0 fmol of the substrate/min/mg of protein) and in the small intestine (23.4 0.9 fmol/min/mg of protein) with its gradual decrease when progressing down the gastrointestinal tract. This result confirms the hypothesis of enkephalinase participation in protein hydrolysis processes.

Digestive System↗